Imperial Moth Eggs Arrive

The Imperial Moth eggs (Eacles imperialis) we purchased from a New York breeder arrived today.

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Today we had Imperial Moth (Eacles imperialis) eggs arrive from a New York breeder that were presumably laid on 8/2. The eggs came by envelope in a metal tube with cotton stuffed on one end. We had actually purchased 3 dozen (36) eggs but our very generous seller gave us 52, 16 extras since this species apparently has a relatively low hatch rate compared to other Saturniids. After taking all the eggs out, we put them in a petri dish and set them in a safe place with no direct sunlight. Below are pictures of the eggs. 

They are a shiny yellow and some have a little brown on the edges. A few have very faint whitish crescent which should be the developing caterpillar. The actual shell of the eggs seems to be translucent but the yolk inside gives them color; in some you can even see air bubbles inside. All the eggs should be alive so far since none have collapsed and are all yellow in color meaning they are developing (fresh eggs are white). It's been about 10 days since they were laid, so they should be hatching any day now. 

Just some background information on the Imperial Moth -- it is one of North America's largest moths with a wingspan approaching 6 inches and a caterpillar length approaching 4 inches. It's native range is in eastern North America but has become increasing scarce in the northern parts of its range. Like the other members of the Ceratocampinae and also Sphingidae, the caterpillars pupate in an earthen chamber. Also, like all Saturniidae and some Sphingidae (Smerinthinae), the adults lack feeding mouth parts and devote their short lifespan to reproduction.

We wanted to try rearing this species for multiple reasons. First, we really wanted to try a member of the Royal Moths (Ceratocampinae) since we had previously only tried Saturniinae. Also, it's a huge and attractive moth, larger than the Cecropia Moth by weight and wingspan despite that the latter is often cited as North america's largest moth because it has the largest wing surface area. And finally, for convenience purposes, we will be graduating high school in the spring of 2017 and really need to rear as many species as possible before we leave for college, preferably THIS year so we can see the adult moths eclose the following spring.

It's quite late in the season to begin rearing caterpillars, but for the Imperial Moth, this is still an appropriate time since the adults are usually on the wing from June-August in the northern parts of its range. However, despite that this is the normal breeding time for this species, we are in a bit of a dilemma for choosing host plants. We have plenty of pine (Pinus) growing around here, and even a small one in our yard that we could sleeve up, but apparently pine, though a commonly utilized host, is not as nutritious as deciduous hosts and produces smaller adults. However, we are afraid the deciduous hosts around here such as sweet gum (Liquidambar) might lose their leaves by the time the caterpillars are mature in early October. Another host is oak (Quercus), but the evergreen Coast Live Oaks (Quercus agrifolia) here usually have poor quality leaves that are extremely tough and prickly (can pierce skin), and the Pin Oak (Quercus palustris) that we are currently feeding our Polyphemus caterpillars is too far to pick from everyday once school starts and might lose its leaves soon just like the sweet gum. Besides pine, sweet gum, and oaks, there are a few other hosts we could use but all are not very common such as maple (Acer). However, according to a Utah breeder (not the one we purchased from), Imperial caterpillars will accept and actually produce the largest (yes, largest) moths on willow (Salix) despite that this is not a reported host in the wild.  If this is true, then we are in luck because there are some extremely high quality willow trees here that are probably evergreen. So far we are probably just going to stick with with pine, sweet gum, and/or willow when they hatch. We will try moving them onto willow first, but if this fails then we will move most on pine and some on sweet gum. 

- Alan